Separable monitoring device and method

ABSTRACT

A patient monitoring device includes reusable and disposable portions. The disposable portion includes two or more electrodes for coupling to the skin of the patient, a battery, and a first set of electrical contacts. The reusable portion includes a processor, memory, a second set of electrical contacts, and sensing circuitry coupled to the at least two electrodes, wherein the reusable portion is mechanically coupleable to the disposable portion and wherein the reusable portion is electrically coupleable to the disposable portion through the first and second electrical contacts. The sensing circuitry and the processor are powered from the battery through the coupled first and second electrical contacts, and wherein when the reusable portion and the disposable portion are mechanically uncoupled after having been mechanically coupled, the disposable portion is rendered unusable by the process of mechanically uncoupling the reusable portion and the disposable portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention is a divisional of U.S. application Ser. No.14/627,567 filed Feb. 20, 2015, which claims priority to U.S.Provisional Patent Application No. 61/943,684, titled “PhysiologicalMonitoring Device and Method”, filed Feb. 24, 2014 and U.S. ProvisionalPatent Application No. 61/948,973, titled “Separable Monitoring Deviceand Method”, filed Mar. 6, 2014, both of which are incorporated byreference in their entirety. A claim of priority is made.

BACKGROUND OF THE INVENTION

Various devices have been developed for monitoring physiologicalparameters of a patient, for the detection, diagnosis, or prediction ofhealth problems. For example, U.S. Patent Application Publications2009/0076344 and 2009/0076345 describe adherent patches that monitorpatient parameters such as tissue impedance, electrocardiogram signals,and other parameters, and transmit information wirelessly to a centralserver.

It is desirable that the cost of monitoring devices and services be keptlow.

BRIEF SUMMARY OF THE INVENTION

In one aspect, a monitoring device for monitoring one or morephysiological parameters of a patient comprises a disposable portioncomprising at least two electrodes for coupling to the skin of thepatient, a battery, and a first set of electrical contacts. Themonitoring device further comprises a reusable portion comprising aprocessor, memory, a second set of electrical contacts, and sensingcircuitry coupled to the at least two electrodes. The reusable portionis mechanically coupleable to the disposable portion and the reusableportion is electrically coupleable to the disposable portion through thefirst and second electrical contacts. When the reusable portion and thedisposable portion are electrically coupled through the first and secondelectrical contacts, signals from the at least two electrodes are passedto the sensing circuitry and processed by the processor. The sensingcircuitry and the processor are powered from the battery through thecoupled first and second electrical contacts, and when the reusableportion and the disposable portion are mechanically uncoupled afterhaving been mechanically coupled, the disposable portion is renderedunusable by the process of mechanically uncoupling the reusable portionand the disposable portion.

In another aspect, a monitoring device for monitoring one or morephysiological parameters of a patient includes a disposable portion anda reusable portion. The disposable portion comprises at least twoelectrodes for coupling to the skin of the patient, a battery, and afirst set of electrical contacts. The reusable portion comprises aprocessor, memory, a second set of electrical contacts, and sensingcircuitry coupled to the at least two electrodes, wherein the reusableportion is mechanically coupleable to the disposable portion such thatwhen the reusable portion and the disposable portion are mechanicallycoupled they form a water-resistant unit, and wherein the reusableportion is electrically coupleable to the disposable portion through thefirst and second electrical contacts. In addition, when the reusableportion and the disposable portion are electrically coupled through thefirst and second electrical contacts, signals from the at least twoelectrodes are passed to the sensing circuitry and processed by theprocessor, and wherein the sensing circuitry and the processor arepowered from the battery through the coupled first and second electricalcontacts. In addition, the reusable portion and the disposable portionare separable, and wherein the reusable portion can be used with adifferent disposable portion.

A monitoring device for monitoring an electrocardiogram of the patientincludes a disposable portion and a reusable portion. The disposableportion includes a shell having a bay and a first surface for adheringto the skin of a patient. The disposable portion includes at least twoskin electrodes on the first surface of the shell, a battery housedwithin the shell, and a first set of electrical contacts within the bayand in electrical communication with the battery and the skinelectrodes. The reusable portion is releasably received and mechanicallycoupled within the bay of the disposable portion. The reusable portioncomprises a monitoring circuit and a second set of electrical contactsin electrical communication with the monitoring circuit. The bay of thedisposable portion and the reusable portion include interlockingfeatures that releasably lock the reusable portion in the bay of thedisposable portion with the second set of electrical contacts inelectrical contact with the first set of electrical contacts such thatthe skin electrodes and battery of the disposable portion are inelectrical communication with the monitoring circuit of the reusableportion. The bay includes first and second ends, the first set ofelectrical contacts being arranged along the first end, the interlockingfeatures including a breakable feature arranged along the second end.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an exploded view of a monitoring device inaccordance with embodiments of the invention.

FIG. 1B shows a reverse angle view of a disposable portion of themonitoring device of FIG. 1A.

FIGS. 2A and 2B illustrate the process of mechanically coupling areusable portion and a disposable portion of the monitoring device ofFIGS. 1A and 1B.

FIG. 3 illustrates a conceptual schematic view of an electronicarchitecture of the monitoring device of FIGS. 1A and 1B, in accordancewith embodiments of the invention.

FIG. 4 illustrates the monitoring device of FIGS. 1A and 1B adhered to apatient.

FIG. 5 illustrates the construction of an embodiment of a disposableportion in more detail.

FIG. 6 illustrates an underside view of a foam cover, in accordance withembodiments.

FIG. 7 illustrates a technique for rendering the disposable portion ofthe device of FIGS. 1A and 1B unusable, according to embodiments.

FIGS. 8A and 8B show additional details of the technique of FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1A illustrates an exploded view of a monitoring device 100 inaccordance with embodiments of the invention. Monitoring device 100 iscapable of monitoring one or more physiological parameters of a patient.Device 100 includes a disposable portion 101 and a reusable portion 102.

FIG. 1B shows a reverse angle view of disposable portion 101. Disposableportion 101 includes a number of electrodes 103 a-103 d. While fourelectrodes are shown in this example, different numbers of electrodesmay be provided, depending on the physiological parameter or parametersa particular device is intended to monitor. Electrodes 103 a-103 d areconfigured to couple to the skin of the patient. For example, device 100may be adhered to the thorax of the patient using an adhesive layer onthe bottom side of bottom layer 104. Device 100 may be initiallysupplied with a release layer (not shown) that protects the adhesive andelectrodes during shipping and storage, and that is removed beforeadhering the device to the patient. In some embodiments, electrodes 103a-103 d are overlaid by a gels held in pockets 105 a-105 d formedbetween bottom layer 104 and another internal layer. The gels mayenhance electrical contact between electrodes 103 a-103 d and thepatient's skin. Additional details of possible arrangements ofelectrodes, gels, and structural layers usable in embodiments of theinvention may be found in US Patent Application Publication 2011/0144470published Jun. 16, 2011 and titled “Body Adherent Patch with Electronicsfor Physiologic Monitoring”, the entire disclosure of which isincorporated by reference herein for all purposes.

Each of electrodes 103 a-103 d is electrically connected to one of afirst set of electrical contacts 106. For example, electrodes 103 a-103d may be formed on a flexible circuit that includes electrical tracesthat connect electrodes 103 a-103 d to electrical contacts 106.Electrical contacts 106 may be formed on a printed circuit board 107that also includes a connector 108 for receiving a flex circuit or otherconnection to electrodes 103 a-103 d. Some electronic components 109 mayalso be provided on printed circuit board 107. Disposable portion 101also includes a battery (not visible in FIGS. 1A and 1B).

The outer portion of disposable portion 101 may be covered with aflexible, breathable material 110 that is waterproof or water resistant,and is sealed around the edges directly or indirectly to bottom layer104, so that device 100 can withstand being splashed with water withoutcompromising the usability of the device. For example, material 110 maybe a cloth including polyester, polyamide, nylon, and/or elastane(Spandex™). The breathable fabric may be coated or otherwise configuredto make it water resistant or waterproof. In other embodiments, theouter portion of disposable portion 101 may be made of a non-breathablematerial, and moisture egress from the patient's skin may be provided byopenings within the material.

Reusable portion 102 contains electronic components as described in moredetail below. Reusable portion 102 includes a second set of electricalcontacts (not visible in FIGS. 1A and 1B) that are complementary tofirst electrical contacts 106, so that signals from electrodes 103 a-103d are coupled to reusable portion 102 when the two sets of contacts areengaged. Power from the battery in disposable portion 101 is alsotransferred through electrical contacts 106, to power reusable portion102.

In this example, reusable portion 102 snaps securely into a frame formedaround pocket (or bay) 111. Preferably, reusable portion 102 is a sealedmodule that can also withstand being splashed with water. Preferably,when disposable portion 101 and reusable portion 102 are mechanicallycoupled together, they form a water resistant unit. For example,reusable portion 102 may fit snugly enough into pocket 111 tosubstantially prevent the ingress of splashed water into pocket 111, ormay be sealed using a gasket or the like. Preferably, the adhesive onbottom side 104 is also water resistant and has a high moisture vaportransmission rate, so that device 100 can be worn for extended periodswhile allowing the user to participate in normal daily activities,including showering. For example, in some embodiments, bottom layer 104may be made of MED 5021 polyurethane film available from Avery DennisonCorporation of Pasadena, Calif., USA, or Tegaderm™ film available fromthe 3M Company of St. Paul Minn., USA, or a similar material. Thematerial of bottom layer 104 may have a moisture vapor transmission rateof at least 100 g/m²/24 hrs, at least 400 g/m²/24 hrs, or anothersuitable value. In some embodiments, device 100 can be worn for up to180 hours or more without being removed from the patient.

Button 112 may be actuated by the patient as is explained in more detailbelow.

FIGS. 2A and 2B illustrate the process of mechanically coupling reusableportion 102 with disposable portion 101. In FIG. 2A, reusable portion102 has been positioned to hook the far edge of reusable portion 102(not visible in FIG. 2A) with the far edge of pocket 111. A snap feature201 is configured to engage with a complementary feature (not visible)on the near edge of pocket 111. Reusable portion 102 is then rotateddownward to engage snap feature 201, so that device 100 is assembledinto the configuration shown in FIG. 2B. Preferably, device 100 is notdisassemblable by the user to separate reusable portion 102 fromdisposable portion 101.

FIG. 3 illustrates a conceptual schematic view of an electronicarchitecture of monitoring device 100, in accordance with embodiments ofthe invention. Disposable portion 101 includes electrodes 103 a-103 d,and a primary battery 301. Primary battery 301 preferably has sufficientenergy storage capacity to power monitoring device 100, includingreusable portion 102, for a complete monitoring period, for example upto 180 hours or more. Electrodes 103 a-103 d and the terminals ofbattery 301 are connected through electrical contacts 302 to reusableportion 102. Electrical contacts 302 include first electrical contacts106 on disposable portion 101, as well as second electrical contacts 316on reusable portion 102. Electrical contacts 302 are engaged whendisposable portion 101 and reusable portion 102 are assembled to eachother.

Disposable portion 101 also includes a disposable portion identifier303, which is also communicated to reusable portion 102 throughelectrical contacts 302. The depiction of disposable portion identifier303 and its connection to reusable portion 102 in FIG. 3 is conceptual,and this functionality may be implemented using any suitable techniqueor combination of techniques. For example, disposable portion identifiermay be stored in a memory addressable through electrical contacts 302,may be configured using a set of switches or fusible links that can besensed through electrical contacts 302, may be repeatedly seriallytransmitted on a signal line, or may be implemented in some other way.The storage and transmission of disposable portion identifier 303 may bepassive (not requiring any power) or may require electrical power, inwhich case power is supplied from primary battery 301, from the signallines of processor 307 described below, or from another source. Powerdistribution lines are not depicted in FIG. 3 so as not to obscure theoperation of the device in unnecessary detail. Similarly, certainconnections between components are simplified. For example, certainconnections that involve multiple signal paths or a combination of powerand signal paths may be shown using a single line. In other cases,amplification or buffering circuitry and the like may not be shown.

Reusable portion 102 comprises a secondary battery 304 and a real timeclock 305 powered by secondary battery 304. Secondary battery 304 maybe, for example, a rechargeable lithium ion battery or another suitablekind of battery. Real time clock 305 enables reusable portion 102 tomaintain an accurate time, even when reusable portion 102 is notconnected to any disposable portion 101, and does not receive power fromprimary battery 301. Because secondary battery 304 need only power realtime clock 305, it may have a smaller energy storage capacity thanprimary battery 301. Reusable portion 102 also comprises chargingcircuit 306, for charging secondary battery 304 using energy fromprimary battery 301, when available.

In other embodiments, a single battery may be used, residing in reusableportion 102. The single battery may have enough capacity to powermonitoring device 100 for up to 180 hours or more, and may berechargeable through electrical contacts such as contacts 316 onreusable portion 102. The single battery may also be able to power realtime clock 305 for longer periods. Any necessary power for components indisposable portion 101 may be transferred through the contacts. Thesingle battery may be recharged at any suitable time, for example beforereusable portion 102 is installed in a new disposable portion 101, orwhen data is read from reusable portion 102 at the end of a monitoringperiod as is described in more detail below. In other embodiments, thesingle battery may be replaceable, and may be replaced each timereusable portion 102 is assembled into a new disposable portion 101. Thereplaced battery may preferably be rechargeable off line.

Referring again to FIG. 3, reusable portion 102 also includes aprocessor 307 for controlling the operation of monitoring device 100,analyzing signals, and communicating with other devices. Processor 307may be, for example, a microprocessor as depicted in FIG. 3, or may be amicrocontroller, digital signal processor, programmed gate array, oranother kind of circuitry that can perform the necessary functions.

Signals from electrodes 103 a-103 d are coupled to processor 307 throughcontacts 302. The coupling may be direct, or additional circuitry may bepresent between electrodes 103 a-103 d and processor 307, for examplesignal conditioning circuitry, drive circuitry, switching circuitry, andthe like. In FIG. 3, such circuitry is depicted as conditioning/drivecircuitry 308. Conditioning/drive circuitry 308 may include, forexample, signal conditioning amplifiers, noise filters, or the like.

In some embodiments, individual ones of electrodes 103 a-103 d mayperform different functions at different times. For example, at onetime, processor 307 may configure monitoring device 100 to measure anelectrocardiogram (ECG) of the patient using two or three of theelectrodes, and at another time, processor 307 may configure monitoringdevice 100 to measure a tissue impedance of the patient by driving aknown alternating current between electrodes 103 b and 103 c, andmeasuring the voltage impressed between electrodes 103 a and 103 d. Inorder that electrodes 103 a-103 d can perform multiple functions,switching circuitry may be provided that switches electrodes betweendriving and sensing modes, for example. Additional details of suchswitching circuitry may be found in U.S. Patent Application PublicationNo. 2009/0076345 published Mar. 19, 2009 and titled “Adherent Devicewith Multiple Physiological Sensors”, the entire disclosure of which isincorporated by reference herein for all purposes.

Reusable portion 102 further includes memory 309 accessible by processor307. While only a single block is shown in FIG. 3, it will be understoodthat memory 309 may comprise one or more kinds of memory, including oneor more of random access memory (RAM), read only memory (ROM), flashmemory, electrically erasable programmable read only memory (EEPROM), orother kinds of memory. Memory 309 may hold instructions for processor307, such that the functions of monitoring device 100 are caused to becarried out when processor 307 executes the instructions. Memory 309preferably also stores a unique reusable portion identifier. Inaddition, data monitored from electrodes 103 a-103 d may be stored inmemory 309, as is described in more detail below.

Reusable portion 102 further includes wireless communication circuitry310 and an antenna 311, for wirelessly transmitting and receivinginformation to and from one or more external devices. For example,wireless communication circuitry 310 may implement a protocol such asBluetooth®, ZigBee®, Wi-Fi®, or another kind of standard or proprietaryprotocol.

Button 112 enables a user of monitoring device 100 to signal processor307. A connector 312 may be provided for communicating with an externaldevice via a cable or other wired connection. Connector 312 may be, forexample, part of a Universal Serial Bus (USB) interface, or another kindof standard or proprietary interface. In some embodiments, anaccelerometer 313 enables measurement of the patient's orientation andactivity level.

One or more light sources 314 may be provided for indicating the stateof monitoring device 100 or for communicating other information. Forexample, light source 314 may be a light emitting diode that is undercontrol of processor 307. Light source 314 may produce light of a singlecolor, or may be multi-colored. Information may be communicated usinglight source 314 by using a particular color, flashing pattern, or both.For example, normal operation may be indicated by a periodic flash ofgreen light from light source 314, and an error condition may beindicated by emitting steady red light. Many other techniques arepossible for communicating information. In some embodiments, more thanone light source 314 may be provided, and information may becommunicated by either or both of the light sources 314.

The brightness of light source 314 may also be controllable, for exampleby changing the duty cycle of a pulse width modulated (PWM) drivingcircuit. In some embodiments, monitoring device 100 includes an ambientlight sensor 317, and adjusts the brightness of light source 314. Forexample, during the day in a brightly lit room, light source 314 may beilluminated brightly, for good visibility. However, at night, in a dimlylit bedroom or darkened hospital ward, the full brightness of lightsource 314 may be distracting, while even a dim light may be readilyvisible. In that case, the brightness of light source 314 may be reducedaccordingly, to reduce the distraction caused by light source 314.

In some embodiments, monitoring device 100 may include a sound generator315, for signaling the patient. Sound generator 315 may be activated tonotify the user of a condition that may compromise the operation ofmonitoring device 100 or for other uses. For example, a signal may beactivated to notify the patient that electrical conductivity to thepatient's skin has been lost, that wireless connectivity to intermediatedevice 403 has been lost, or that some other urgent condition exists.The nature of the condition may be indicated by one or more of thepitch, loudness, or beeping pattern of sound generator 315, or by someother aspect of the generated sound.

Due to variations in hearing ability between patients, some patients maybe able to hear frequencies that other patients may not, and vice versa.In order to improve the chance that a particular patient will be able tohear sound generator 315, sound generator 315 may be controlled toproduce sounds containing multiple or different frequencies. In oneembodiment, sound generator 315 is driven at 850 Hz and then at 950 Hz.In other embodiments, multiple frequencies may be generatedsimultaneously.

In some embodiments, monitoring device 100 may include a humidity sensor317, configured to detect the ingress of water into reusable portion102. For example, humidity sensor 317 may be a resistive or capacitivehumidity sensor. Humidity sensor 317 is preferably coupled to processor307, which can monitor the output of humidity sensor 317 to detect athreshold level of moisture or a change in moisture inside reusableportion 102 that might indicate ingress of moisture into reusableportion 102. When moisture ingress is detected, processor may signal theuser using light source 314 or sound generator 315, may transmit anindication of the detection to a remote server using wirelesscommunication circuitry 310, or may take another action.

Preferably, before use of a particular monitoring device 100, the uniqueidentifiers of disposable portion 101 and reusable portion 102 arerecorded and matched in a database, to indicate that the two portionsare authorized for use together. This pairing may be done beforeshipment of the device to a particular patient. As is explained in moredetail below, reusable portion 102 may be used serially with a number ofdisposable portions 101. In this case, a pre-packaged set of onereusable portion 102 and a number of disposable portions 101 may beshipped together, and their unique identifiers may be recorded as a setin the database.

When disposable portion 101 and reusable portion 102 are assembledtogether, processor 307 may request the unique identifier of disposableportion 101. If no unique identifier is received, it may be assumed thata malfunction has occurred, or that the disposable portion may becounterfeit and not trustworthy, or that some other circumstance hasoccurred that may prevent reliable monitoring. If no identifier isreceived from disposable portion 101, processor 307 may simply refuse toproceed with monitoring.

In other embodiments, reusable portion 102 may be loaded at the time ofshipment with the unique identifiers of all disposable portions 101 withwhich reusable portion 102 is intended to be used. On power up, reusableportion 102 may read the unique identifier of the particular disposableportion 101 into which it has been assembled, and compare the identifierwith its stored list of acceptable identifiers. If the identifier is notfound, reusable portion 102 may simply not initiate monitoring. If theidentifier is found in the list, then monitoring begins as normal.

In other embodiments, reusable portion 102 may retrieves uniqueidentifier 303 of disposable portion 101 and report it, along with theunique identifier of reusable portion 102, to remote server 402 fordetermination whether the two portions are intended to be used together.If records indicate that the two portions are not intended for usetogether, remote server 402 may alert monitoring personnel. Even when amismatch is detected, monitoring device 100 may commence monitoring,including the storing of sampled data and the transmission of eventreports, and remote server 402 may accept the transmitted data. However,the fact that an unexpected disposable portion 101 is detected mayindicate the possibility of product misuse or unreliable monitoring,which can then be investigated

Assuming that monitoring is to proceed, monitoring device 100 is adheredto a patient 401, for example as shown in FIG. 4. In some uses,disposable portion 101 may be adhered to patient 401 and then reusableportion 102 assembled into it, and in other uses, monitoring device 100may be assembled before being adhered to patient 401.

Under control of processor 307, monitoring device 100 may monitor one ormore different physiological parameters of patient 401. For example, anelectrocardiogram (ECG) of patient 401 may be recorded from signalssampled from two or more of electrodes 103 a-103 d. In some embodiments,the ECG is taken by sampling the voltage between two of electrodes 103a-103 d with a frequency rapid enough to detect the subtle electricalsignals produced by the heart of patient 401. For example, the voltagemay be sampled with a frequency of 50-1000 Hz. In one embodiment, thevoltage is sampled with a frequency of 200 Hz (once every 5milliseconds). The voltage may be sampled using an analog-to-digitalconverter (ADC), for example an ADC built into or connected to processor307.

The circuitry used to sense signals from electrodes 103 a-103 d may becollectively referred to as sensing circuitry. For example, sensingcircuitry may include signal conditioning circuitry 308 and processor307, as well as various amplifiers, ADCs, and the like. Many differentarrangements are possible.

In some embodiments, the ECG data may be filtered to remove the effectsof interference from common noise sources such as the mains power line.For example, a raw ECG signal may be sampled at a higher frequency thanits ultimate recorded sampling frequency, and digitally filtered. In oneembodiment, the raw ECG sampling is done at 600 Hz, the raw data aredigitally filtered to remove 50 Hz or 60 Hz power line noise, and thedata are downsampled to 200 Hz for recording.

More information about the recording of an ECG may be found in U.S.Patent Application Publication No. 2013/0274584 published Oct. 17, 2013and titled “Heuristic Management of Physiological Data”, the entiredisclosure of which is incorporated by reference herein for allpurposes.

In some embodiments, the sampled data (e.g. the 200 Hz ECG voltagesamples) are stored in a non-volatile portion of memory 309. Dependingon the resolution of the ADC, each sample may require 8-16 bits ofstorage, such that 180 hours of sampled data can be conveniently storedin available memory sizes. For the purposes of this disclosure, thisstored information may be referred to as “complete” data.

All monitored information may be encrypted and stored in memory 309,such that the data can be decrypted only using a key or keys. Encryptionmay be performed using an algorithm such as RSA, DSS, or another kind ofalgorithm. Thus, should reusable portion 102 be lost after monitoringthe condition of a particular patient, it will not be possible for anunauthorized party to reconstruct sensitive medical information aboutthe patient. In addition, any transmissions of data may also beencrypted.

Another example of a physiological parameter that may be monitored bymonitoring device 100 is the patient's tissue hydration level. Increasedfluid retention in the tissues of the body is a symptom of acute cardiacdecompensation heart failure, and may be reflected in the electricalimpedance of the patient's tissue. Tissue impedance may be measured, forexample, by forcing a known electrical current through outer electrodes103 b and 103 c, and measuring the voltage impressed between electrodes103 a and 103 d. The current may be alternating current, at anexcitation frequency selected to most effectively characterize thetissue hydration. More information about tissue hydration measurementmay be found in U.S. Patent Application Publication No. 2009/0076345previously incorporated by reference, and U.S. Patent ApplicationPublication No. 2009/0076344 published Mar. 19, 2009 and titled“Multi-Sensor Patient monitor to Detect Impending CardiacDecompensation”, the entire disclosure of which is incorporated byreference herein for all purposes.

Because tissue impedance is a slowly-changing parameter, impedance dataneed not be sampled as often as ECG data. For example, tissue impedancedata samples may be taken and stored at a sampling frequency of 0.1 to10 Hz (one sample every 0.1 to 10 seconds), or at another suitablefrequency. Note that this sampling frequency is independent of theexcitation frequency of the AC current used in taking the impedancemeasurements.

Still another example of a physiological parameter that may be monitoredusing monitoring device 100 is the patient's respiration. For example,the patient's breathing rate, breath volume, or other breathingcharacteristics may be monitored. Such breathing parameters may also berelevant in the diagnosis or prediction of acute decompensated heartfailure. For example, a trend toward an increased breathing ratecombined with reduced breath volume, so-called “shallow” breathing maybe suggestive of impending heart failure.

The patient's breathing rate and volume may also be inferable fromtissue impedance measurements, as the tissue impedance observed bymonitoring device 100 may vary by a measurable amount as the patientinhales and exhales. (These variations are preferably filtered out whencharacterizing the impedance itself.) Impedance variations occurring inthe frequency range of normal breathing may be analyzed to characterizethe patient's breathing. More information about the relationship ofimpedance and respiration may be found in U.S. Patent ApplicationPublication No. 2011/0245711, published Oct. 6, 2011 and titled “Methodand Apparatus for Personalized Physiologic Parameters”, the entiredisclosure of which is incorporated by reference herein for allpurposes.

Impedance samples for characterizing respiration may be taken and storedwith a sampling frequency of 2 to 10 Hz, or another suitable samplingfrequency. In one embodiment, data samples for measuring respiration aretaken and stored with a sampling frequency of 4 Hz.

Other examples of physiological parameters that may be monitored usingmonitoring device 100 are aspects of the patient's orientation,activity, or other parameters that may be measured using accelerometer313. For example, signals produced by accelerometer 313 may be used todetermine if the patient is lying down or is upright. In addition, thesignals may be used to determine the patient's activity level, forexample whether the patient is sedentary, exercising, or the like. Insome cases, the intensity or type of exercise may be ascertainable fromthe accelerometer signals. Certain abrupt accelerometer signals mayindicate that the patient has fallen.

Accelerometer signals may be taken and stored with a sampling frequencyof 0.1 to 10 Hz, or another suitable sampling frequency. In oneembodiment, data samples from accelerometer 313 are taken and storedwith a sampling frequency of 0.25 Hz, or one sample every 4 seconds.

In addition to storing sampled data from the various sensors onmonitoring device 100, processor 307 may continually monitor and analyzethe sampled data to detect physiological events of patient 401. Forexample, the ECG samples may be compared with templates characterizingdifferent possible arrhythmias, and the occurrence of an arrhythmia maybe considered an event. In another example, ongoing impedancemeasurements may indicate that the patient's tissue hydration haselevated above a predetermined threshold value, as compared with abaseline value measured at the beginning of the monitoring period.Because of the significance of tissue hydration in acute decompensatedheart failure, this rise in tissue hydration may be considered asignificant physiological event. In another example, an accelerometerreading that indicates that the patient has fallen may be considered aphysiological event.

Event recognitions may also be derived from combinations of sensor data.For example, a rise in tissue hydration combined with a reduction inbreath volume as compared with baseline values may be considered aphysiological event. In another example, an increase in heart rate asindicated by the ECG data that is not accompanied by a commensurateincrease in physical activity as indicated by signals from accelerometer313 may be considered a physiological event. Many other eventdefinitions are possible.

Example monitoring device 100 can report some or all detected events asthe events occur, via wireless communication circuitry 310. When aparticular arrhythmia is detected, monitoring device 100 may transmit areport of the physiological event via wireless communication circuitry310 to an external device.

Referring again to FIG. 4, monitoring device 100 may report eventindications to a remote server 402 via an intermediate device 403. Forthe purposes of this disclosure, either remote server 402 orintermediate device 403 may be considered an “external device” withwhich monitoring device 100 communicates.

Intermediate device 403 may communicate with monitoring device 100wirelessly via link 404, which may be a short-range wireless link suchas a Bluetooth®, ZigBee®, Wi-Fi® or other kind of standard orproprietary wireless link. In turn, intermediate device 403 communicateswith remote server 402 using communication link 405, which may be awide-area wireless connection such as a cellular telephone connection,or may be a wired connection. This arrangement enables patient 401 to goabout his or her daily activities while monitoring is ongoing and eventsare reported. Remote server 402 may be, for example, at a monitoringfacility, health care facility, or any other location worldwide wherelink 405 can be made. In other uses, remote server 402 may be adjacentpatient. In some embodiments, no intermediate device may be necessary,and monitoring device 100 may communicate directly with a server thatreceives event reports.

In FIG. 4, intermediate device 403 is depicted as being connected tomains power outlet 406. For example, patient 401 may plug inintermediate device 403 at the patient's home or office. In otherembodiments, intermediate device may also or alternatively be batterypowered, enabling further flexibility on the part of patient. Forexample, patient 401 may carry a battery powered intermediate device 403while going about daily errands. So long as link 405 is maintained, forexample so long as patient 401 remains in an area with cellulartelephone coverage, event reports can be transmitted promptly to remoteserver 402.

An event report may indicate that an event has been detected, maydescribe the event, and may also include a portion (“snippet”) of thesampled data that prompted the event report. For example, if analysis ofa portion of the sampled ECG determines that a particular arrhythmia hasoccurred, the event report may simply indicate that the arrhythmia wasdetected at a certain time. However, in some embodiments, report mayalso include sampled ECG data showing the arrhythmia occurring. Aphysician or other health care professional may use the transmitted datato verify that the event actually occurred, to evaluate the severity ofthe event, or for other purposes.

Even if events are not detected, monitoring device 100 may periodicallyreport to remote server. For example, during ECG monitoring, monitoringdevice 100 may send an ECG data snippet after a predetermined time haselapsed without any event detections. The predetermined time may be anysuitable interval, for example one hour, two hours, four hours, oranother interval.

Patient 401 may also be able to trigger the sending of a data snippetusing button 112. Considered another way, a press of button 112 may beconsidered an event, to which monitoring device 100 reacts bytransmitting a data snippet. For example, if patient 401 experiences asymptom that he or she suspects may be related to the condition forwhich he or she is being monitored, patient 401 can press button 112, tocause monitoring device 100 to send data encompassing the time justbefore the button press to remote server 402 and preferably a period oftime after the button press. For example, upon a press of button 112,monitoring device 100 may record an additional 30 seconds of data, andthen transmit to server 402 45 seconds of data, including the 15 secondsbefore and the 30 seconds after the press of button 112. Of course,other intervals may be used, and the time period before the button pressfor which data is transmitted need not be the same as the time periodafter the button press for which data is transmitted. Examples ofsymptoms that may prompt a patient to press button 112 may includedizziness, syncope, chest pain, shortness of breath, or other symptoms.

Button 112 may activate a simple mechanical switch that makes or breakselectrical contacts as shown in FIG. 3, or may be another kind of inputdevice. For example, button 112 may be implemented with a magneticdetector such as a Hall effect sensor coupled to processor 307, and theuser may signal monitoring device 100 to capture and send a snippet ofdata by placing a magnet near reusable portion 102. In some embodiments,monitoring device 307 may preferably provide feedback to the userregarding the request to transmit a data snippet. For example,monitoring device may flash light source 314 or generate a sound usingsound generator 315 to signal the user. Monitoring device 100 may signalthe user of such events as that the button press or other request signalwas received, that the data snippet was collected and sent, or otheraspects of snippet collection and transmission.

In some embodiments, communication between remote server 402 andmonitoring device 100 may be bidirectional. This capability may be usedfor a variety of purposes. For example, remote server 402 may downloadsoftware updates to monitoring device 100, for upgrading thecapabilities of monitoring device 100, for configuring monitoring device100 to perform a different kind of monitoring than it has beenperforming, or for other purposes. In one example scenario, a datasnippet transmitted as a result of a press of button 112 by patient 401may prompt a reviewing physician to suspect a medical condition that hadpreviously not been suspected for patient 401. In that case, remoteserver may send commands to monitoring device 100 reconfiguring it toadd monitoring additional physiological parameters.

In another use of bidirectional communication, remote server may requestsnippets of sampled data “on demand” by sending requests to monitoringdevice 100. For example, a physician reviewing an event report sent bymonitoring device 100 may wish to see more ECG data than was sent bymonitoring device with the event report, or may wish to see data from adifferent kind of sensor present on monitoring device. In an examplescenario, patient 401 may feel dizzy and press button 112, promptingmonitoring device 100 to send a snippet of ECG data to remote server402. If a review of the data snippet does not reveal any abnormalitythat might explain the patient's symptoms, a reviewing physician mayrequest that respiration and activity data from just before the time ofthe button press also be transmitted, in case the additional data mightassist in determining the cause of the patient's symptoms.

In some embodiments, monitoring device 100 or remote server 402 maymonitor the quality of the electrode contact with the patient's skin.For example, if monitoring device 100 or remote server 402 receives atissue impedance reading that is higher than normal bounds for humantissue, the reading may be flagged as possibly indicating a loss ofcontact between the patient's skin and one or more of electrodes 103a-103 d. Any of various actions may be taken upon the suspecteddetection of a loss of electrode contact. For example, monitoring device100 may use light source 314 or sound generator 315 to signal apotential problem to the patient, using a light pattern, light color, orsound that signals the user to contact a help line for instructionsabout responding to the problem. In another scenario, remote server 402may flag the potential loss of contact, and a customer servicerepresentative may call the patient directly to ask what may haveprecipitated the suspect reading or readings. If electrode contact hasbeen lost, the patient may be directed to visit a clinic of othermedical facility for replacement of disposable portion 101. In someembodiments, a single suspect impedance reading may not triggerintervention, but action may be taken if the elevated impedance persistsfor a predetermined period, for example a few minutes to a few hours.

In some embodiments, monitoring device 100 can be used for extendedmonitoring through the use of multiple disposable portions 101 with asingle reusable portion 102. For example, each disposable portion 101may have a usable life shorter than the period for which monitoring isdesired. In some embodiments, each disposable portion 101 can be usedfor over one week or more, for example 180 hours or more, withoutreplacement. The useful life of disposable portion 101 may be limited bythe capacity of battery 301, the ability of the adhesive holding thedevice to the patient's skin to maintain good electrical contact betweenelectrodes 103 a-103 d and the patient's skin, and other factors.

When a disposable portion 101 has reached the end of its useful life,the patient preferably returns to a clinic or other medical facility forreplacement of disposable portion 101. Monitoring device 100 is removedfrom the patient's skin, and reusable portion 102 is separated fromdisposable portion 101. In some embodiments, the separation ofdisposable and reusable portions 101 and 102 renders disposable portion101 unusable. For example, the act of removing reusable portion 102 maydamage electrical traces within disposable portion 101, may damage themechanical features that hold the two portions together, or may causeother damage to disposable portion 101. Rendering disposable portion 101unusable discourages attempted reuse of disposable portion 101, whichcould result in unreliable monitoring.

If a reused disposable portion 101 were to be assembled with aparticular reusable portion 102, the attempted reuse may be detected.For example, if the reused disposable portion 101 has not been pairedwith the particular reusable portion 102, the reusable portion 102 mayrefuse to operate or may report the mismatch. Or data transfers frommonitoring device 100 may include the unique identifiers of disposableportion 101 and reusable portion 102, and remote server 402 may detectthe reuse when data is received bearing a disposable portion identifierfor which data already exists from a prior monitoring session.

During the replacement process, the sampled data stored in reusableportion 102 may be read through connector 312. For example, a suitablecable may be attached between connector 312 and a computer system orother reader, and the data transferred to the reading device. In otherembodiments, reusable portion 102 may be placed in a reading deviceconfigured to make contact with connector 312 on reusable portion 102.The reading device may be connected to a computer system that ultimatelyreceives the data. Preferably, the retrieved data is associated with anyevent reports and data snippets received during monitoring of patient401.

As will be appreciated, monitoring device 100 may thus make efficientuse of resources, while communicating potentially urgent information inreal time. The ongoing analysis of the sampled data and real timereporting of physiological events ensures that potentially urgent orsignificant events can be reviewed nearly as they occur. Thus, it may beunnecessary to transmit the entire set of sampled data wirelessly. Inany event, transmitting the entire sampled data set wirelessly may beexpensive or impracticable. However, the data may be useful for furtheranalysis of the patient's condition, and it is therefore valuable forthe data to be preserved and stored. Since urgent situations can beaddressed with event reports and possible “on demand” retrieval ofadditional sampled data, it may not be urgent for the complete data toreach server 402 or another storage site. Transferring the complete datavia cable or other wired connection during an office visit may completethe transfer quickly and at low cost.

Reusable portion 102 can then be assembled into a new disposable portion101, and the resulting monitoring device 100 can be re-adhered to thepatient's skin. Upon each reassembly, reusable portion 102 retrieves theunique identifier 303 of the new disposable portion 101 and a check ismade, for example by reusable portion 102 or remote server 402.Monitoring can then continue for another period, up to the useful lifeof the new disposable portion 101. Many changes of disposable portion101 may be performed, so that a patient may be monitored for up to 90days or more.

Once monitoring of a patient is completed, reusable portion 102 may becleaned, for example disinfected, so that it can be reused with adifferent patient. The architecture of monitoring device 100 may enablereusable portion 102 to be sealed from the external environment, andtherefore able to withstand many cleaning and disinfection cycles sothat reusable portion 102 can have an extended useful life. For example,because secondary battery 304 inside reusable portion 102 is re-chargedfrom primary 301 in disposable portion 101, there is no need to openreusable portion 102 to change secondary battery 304. Also, sincereusable portion 102 communicates wirelessly, the number of penetrationsof the shell of reusable portion 102 is minimized.

In addition, the materials of the shell of reusable portion 102 may beselected to be compatible with one or more disinfectant solutions.Similarly, any adhesives used in the assembly of reusable portion 102may be selected to be compatible with the disinfectant of choice. Insome embodiments, a disinfectant and disinfection process may beselected in cooperation with the materials of reusable portion 102, toensure compatibility.

FIG. 5 illustrates an exploded view of the construction of an embodimentof disposable portion 101 in more detail. Bottom layer 104, previouslydescribed, includes an adhesive on its underside (not visible in FIG.5). Bottom layer 104 includes openings 501 a-501 d over which gels 502a-502 d are positioned. Gels 502 a-502 d may be made, for example, ofhydrogel adhesive 9880 available from the 3M Company of St. Paul, Minn.,USA, or another suitable material.

An overlayer 503 is laminated to the top side of bottom layer 104,constraining gels 502 a-502 d and a flex circuit 504 between overlayer503 and bottom layer 104. Overlayer 503 is also breathable, having ahigh moisture vapor transmission rate, for example at least 100 g/m²/24hrs, at least 400 g/m²/24 hrs, or another suitable value. Flex circuit504 includes electrodes 103 a-103 d. Finally, foam cover 505 bonds tothe upper surface of overlayer 503, and defines an opening for pocket111. The interior of pocket 111 is preferably defined by a molded partheld by foam cover 505. Openings 506 remain open to the interior spaceformed between overlayer 503 and foam cover 505.

FIG. 6 illustrates an underside view of foam cover 505, in accordancewith embodiments.

FIG. 7 illustrates a technique for rendering disposable portion 101unusable when reusable portion 102 is removed, according to embodiments.In particular, FIG. 7 provides a magnified cutaway illustrating theremoval of disposable portion 101 from reusable portion 102 using tool704. As illustrated in the magnified cutaway portion, disposable portion101 is configured to receive and retain reusable portion 102. Inparticular, disposable portion 101 includes recess 701, a ledge portion(not visible in this view) that engages snap feature 201 of reusableportion 102, and enclosure walls 702 that intersect with recess 701 atcorners 703.

In one embodiment shown in FIG. 7, wall 702 is weaker than the walls ofrecess 701 or include thin or otherwise weakened areas. As a result,insertion of tool 704 through foam cover 505 and into recess 701 andapplication of force in the direction indicated by the arrow (i.e.,downward rotating about the end of tool 704), results in recess 701being pried away from wall 702 and eventual breaking of a portion ofwall 702. As a result of the dislocation of wall 702, the ledge issimilarly displaced, such that snap feature 201 (shown in FIG. 2A) is nolonger held in place by the ledge. The dislocation of the ledge isillustrated in additional detail in both the unbroken and broken statesIn the process, the ledge for engaging snap feature 201 is displaced andno longer in position to hold reusable portion 102 in disposable portion101.

FIGS. 8A and 8B show top views of recess 701 and the breakage of wall702, resulting in the displacement of ledge 801. In particular, FIG. 8Aillustrates wall 702 in an unbroken state. As a result, ledge 801 ispositioned to engage with snap feature 201 (not shown in this view).Recess 701 is clearly shown, including a portion of recess 701configured to receive tool 704. FIG. 8B illustrates wall 702 in a brokenstate, as a result of tool 704 being placed into recess 701, and rotatedin a downward (in this view, to the right) direction until the appliedforce causes wall 702 to break. As a result of wall 702 breaking, ledge801 is displaced at an angle downward and to the right, such that ledge801 no longer engages snap feature 201. As a result, reusable portion102 can be removed from disposable portion 101, and disposable portion101 is discarded. A benefit of this embodiment is disposable portion 101can no longer be used to retain reusable portion 101, and therefore mustbe discarded as desired.

According to one embodiment of the present invention, a monitoringdevice for monitoring one or more physiological parameters of a patientincludes a disposable portion and a reusable portion. The disposableportion comprises at least two electrodes for coupling to the skin ofthe patient, a primary battery, and a first set of electrical contacts.The reusable portion comprises a processor, memory, a second set ofelectrical contacts, and sensing circuitry coupled to the at least twoelectrodes, wherein the reusable portion is mechanically coupleable tothe disposable portion and wherein the reusable portion is electricallycoupleable to the disposable portion through the first and secondelectrical contacts. When the reusable portion and the disposableportion are electrically coupled through the first and second electricalcontacts, signals from the at least two electrodes are passed to thesensing circuitry and processed by the processor, and wherein thesensing circuitry and the processor are powered from the primary batterythrough the coupled first and second electrical contacts. When thereusable portion and the disposable portion are mechanically uncoupledafter having been mechanically coupled, the disposable portion isrendered unusable by the process of mechanically uncoupling the reusableportion and the disposable portion.

The monitoring device of the preceding paragraph may optionally include,additionally and/or alternatively, one or more of the followingfeatures, configurations and/or additional components.

The reusable portion and the disposable portion may be separable,wherein the reusable portion may be used with a different disposableportion.

In any of the preceding embodiments, the reusable portion may comprise areal time clock and a secondary battery that powers the real time clock,and wherein when the reusable portion and the disposable portion arecoupled through the first and second electrical contacts, the secondarybattery is charged from the primary battery through the first and secondelectrical contacts.

In any of the preceding embodiments, the monitoring device may furthercomprise wireless communication circuitry through which information canbe transmitted to an external device.

In any of the preceding embodiments, the processor may be programmed to:analyze data sampled from the signals from the electrodes; based on theanalysis of the signals form the electrodes, identify a physiologicalevent of the patient; and transmit a report of the physiological eventvia the wireless communication circuitry to the external device.

In any of the preceding embodiments, the processor may be configured tocontinuously record data sampled from the signals from the electrodes inthe memory during monitoring.

In any of the preceding embodiments, the monitoring device may store thedata in an encrypted form.

In any of the preceding embodiments, the processor may be configured tocontinuously transmit recorded data to an external device.

In any of the preceding embodiments, the monitoring device may furthercomprise a data interface comprising a connector, and wherein thecontinuously recorded data may be transmitted to the external device viaa wired connection through the connector.

In any of the preceding embodiments, the processor may be configured to,during monitoring: receive, from an external device via the wirelesscommunication circuitry, a request to transmit a portion of thecontinuously recorded data to the external device; and transmit therequested portion of the continuously recorded data to the externaldevice via the wireless communication circuitry.

In any of the preceding embodiments, the one or more physiologicalparameters monitored by the monitoring device may include anelectrocardiogram of the patient.

In any of the preceding embodiments, the one or more physiologicalparameters monitored by the monitoring device may include a tissueimpedance the patient.

In any of the preceding embodiments, the one or more physiologicalparameters monitored may include a tissue hydration of the patent, andwherein the tissue hydration is derived from the tissue impedance thepatient.

In any of the preceding embodiments, the one or more physiologicalparameters monitored may include any two or more of the parametersselected from the group consisting of an electrocardiogram of thepatient, a tissue impedance the patient, a tissue hydration of thepatient, and an activity level of the patient.

In any of the preceding embodiments, the disposable portion may berendered unusable by breaking a mechanical feature of the disposableportion.

In any of the preceding embodiments, the reusable portion may include aunique reusable portion identifier stored in the reusable portion andaccessible to the processor; and the disposable portion includes aunique disposable portion identifier stored in the disposable portionand accessible to the processor

In any of the preceding embodiments, the reusable portion may be capableof withstanding multiple cleaning and disinfection cycles withoutcompromising the usability of the device

In any of the preceding embodiments, when the reusable portion and thedisposable portion are coupled together, the device may be capable ofwithstanding being splashed with water without compromising theusability of the device

In any of the preceding embodiments, the processor may be initiallyprogrammed such that the device is configured to monitor a particularset of one or more physiological parameters, and wherein the processorcan be reprogrammed such that the device is configured to monitor adifferent set of one or more physiological parameters.

According to another embodiment of the present invention, a monitoringdevice for monitoring one or more physiological parameters of a patientincludes a disposable portion and a reusable portion. The disposableportion includes at least two electrodes for coupling to the skin of thepatient, and a first set of electrical contacts. The reusable portionincludes a processor, memory, a second set of electrical contacts, andsensing circuitry coupled to the at least two electrodes, wherein thereusable portion is mechanically coupleable to the disposable portionand wherein the reusable portion is electrically coupleable to thedisposable portion through the first and second electrical contacts.When the reusable portion and the disposable portion are electricallycoupled through the first and second electrical contacts, signals fromthe at least two electrodes are passed to the sensing circuitry andprocessed by the processor. In addition, the reusable portion includes aunique reusable portion identifier stored in the reusable portion andaccessible to the processor, and the disposable portion includes aunique disposable portion identifier stored in the disposable portionand accessible to the processor.

According to another embodiment of the present invention, a monitoringdevice for monitoring one or more physiological parameters of a patientincludes a disposable portion and a reusable portion. The disposableportion includes at least two electrodes for coupling to the skin of thepatient, and a first set of electrical contacts. The reusable portionincludes a processor, memory, a second set of electrical contacts,sensing circuitry coupled to the at least two electrodes, wirelesscommunication circuitry through which information can be transmitted toan external device, and a data interface comprising a connector fortransmitting data via wired connection using the connector. The reusableportion is mechanically coupleable to the disposable portion and whereinthe reusable portion is electrically coupleable to the disposableportion through the first and second electrical contacts. When thereusable portion and the disposable portion are electrically coupledthrough the first and second electrical contacts, signals from the atleast two electrodes are passed to the sensing circuitry and processedby the processor.

According to another embodiment of the present invention, a monitoringdevice for monitoring one or more physiological parameters of a patientincludes a disposable portion and a reusable portion. The disposableportion includes at least two electrodes for coupling to the skin of thepatient, a primary battery, and a first set of electrical contacts. Thereusable portion comprising a processor, memory, a second set ofelectrical contacts, a secondary battery, a real time clock powered bythe secondary battery, and sensing circuitry coupled to the at least twoelectrodes. The reusable portion is mechanically coupleable to thedisposable portion and wherein the reusable portion is electricallycoupleable to the disposable portion through the first and secondelectrical contacts. When the reusable portion and the disposableportion are electrically coupled through the first and second electricalcontacts, signals from the at least two electrodes are passed to thesensing circuitry and processed by the processor. The sensing circuitryand the processor are powered from the primary battery through thecoupled first and second electrical contacts. When the reusable portionand the disposable portion are coupled through the first and secondelectrical contacts, the secondary battery is charged from the primarybattery through the first and second electrical contacts.

According to another embodiment of the present invention, a monitoringdevice for monitoring one or more physiological parameters of a patientincludes a disposable portion and a reusable portion. The disposableportion includes at least two electrodes for coupling to the skin of thepatient, a battery, and a first set of electrical contacts. The reusableportion includes a processor, memory, a second set of electricalcontacts, and sensing circuitry coupled to the at least two electrodes.The reusable portion is mechanically coupleable to the disposableportion such that when the reusable portion and the disposable portionare mechanically coupled they form a water-resistant unit, and whereinthe reusable portion is electrically coupleable to the disposableportion through the first and second electrical contacts. When thereusable portion and the disposable portion are electrically coupledthrough the first and second electrical contacts, signals from the atleast two electrodes are passed to the sensing circuitry and processedby the processor. The sensing circuitry and the processor are poweredfrom the battery through the coupled first and second electricalcontacts. The reusable portion and the disposable portion are separable,and wherein the reusable portion can be used with a different disposableportion.

The monitoring device of the preceding paragraph may optionally include,additionally and/or alternatively, one or more of the following featuresany of the preceding embodiments.

For example, the battery may be a primary battery.

In any of the preceding embodiments, the reusable portion may include areal time clock and a secondary battery that powers the real time clock,and wherein when the reusable portion and the disposable portion arecoupled through the first and second electrical contacts, the secondarybattery is charged from the primary battery through the first and secondelectrical contacts.

In any of the preceding embodiments, the reusable portion may furtherinclude wireless communication circuitry through which information canbe transmitted to an external device.

In any of the preceding embodiments, the processor may be programmed to:analyze data sampled from the signals from the electrodes; based on theanalysis of the signals form the electrodes, identify a physiologicalevent of the patient; and transmit a report of the physiological eventvia the wireless communication circuitry to the external device.

In any of the preceding embodiments, the processor may be configured tocause data sampled from the signals from the electrodes to becontinuously recorded in the memory during monitoring.

In any of the preceding embodiments, the data may be stored in anencrypted form.

In any of the preceding embodiments, the processor may be configured totransmit the continuously recorded data to an external device.

In any of the preceding embodiments, the monitoring device may furtherinclude a data interface that includes a connector, and wherein thecontinuously recorded data is transmitted to the external device via awired connection through the connector.

In any of the preceding embodiments, the processor may be configured to,during monitoring: receive, from an external device via the wirelesscommunication circuitry, a request to transmit a portion of thecontinuously recorded data to the external device; and transmit therequested portion of the continuously recorded data to the externaldevice via the wireless communication circuitry.

In any of the preceding embodiments, the one or more physiologicalparameters monitored may include an electrocardiogram of the patient.

In any of the preceding embodiments, the one or more physiologicalparameters monitored may include a tissue impedance the patient.

In any of the preceding embodiments, the one or more physiologicalparameters monitored may include a tissue hydration of the patent, andwherein the tissue hydration is derived from the tissue impedance thepatient.

In any of the preceding embodiments, the one or more physiologicalparameters monitored may include any two or more of the parametersselected from the group consisting of an electrocardiogram of thepatient, a tissue impedance the patient, a tissue hydration of thepatient, and an activity level of the patient.

In any of the preceding embodiments, the disposable portion may berendered unusable by breaking a mechanical feature of the disposableportion.

In any of the preceding embodiments, the reusable portion may furtherinclude a unique reusable portion identifier stored in the reusableportion and accessible to the processor; and the disposable portionincludes a unique disposable portion identifier stored in the disposableportion and accessible to the processor.

In any of the preceding embodiments, the reusable portion may be capableof withstanding multiple cleaning and disinfection cycles withoutcompromising the usability of the device.

In any of the preceding embodiments, when the reusable portion and thedisposable portion are coupled together, the device may be able towithstand being splashed with water without compromising the usabilityof the device.

In any of the preceding embodiments, the processor may be initiallyprogrammed such that the device is configured to monitor a particularset of one or more physiological parameters, and wherein the processormay be reprogrammed such that the device is configured to monitor adifferent set of one or more physiological parameters.

According to another embodiment of the present invention, A monitoringdevice for monitoring an electrocardiogram of the patient may include adisposable portion and a reusable portion. The disposable portion mayinclude a shell having a bay and a first surface for adhering to theskin of a patient. The disposable portion may include at least two skinelectrodes on the first surface of the shell, a battery housed withinthe shell, and a first set of electrical contacts within the bay and inelectrical communication with the battery and the skin electrodes. Thereusable portion may be releasably received and mechanically coupledwithin the bay of the disposable portion, the reusable portioncomprising a monitoring circuit and a second set of electrical contactsin electrical communication with the monitoring circuit; the bay of thedisposable portion and the reusable portion including interlockingfeatures that releasably lock the reusable portion in the bay of thedisposable portion with the second set of electrical contacts inelectrical contact with the first set of electrical contacts such thatthe skin electrodes and battery of the disposable portion are inelectrical communication with the monitoring circuit of the reusableportion.

In any of the preceding embodiments, the shell of the disposable portionmay have a second surface and a frame extending into the shell from thesecond surface to define the bay, the first and second surfaces beingformed of one or more flexible, breathable materials, the frame andreusable portion being rigid relative to the first and second surfacesof the disposable portion such that the monitoring device is adapted toconform to the skin of a patient.

In any of the preceding embodiments, the bay may include first andsecond ends, the first set of electrical contacts being arranged alongthe first end, the interlocking features including a breakable featurearranged along the second end.

In any of the preceding embodiments, the first surface of the disposableportion may be formed of material having a high moisture vaportransmission rate.

In any of the preceding embodiments, the first surface of the disposableportion may be formed of material having a moisture vapor transmissionrate of at least 100 g/m²/24 hrs.

In any of the preceding embodiments, the moisture vapor transmissionrate may be at least 400 g/m²/24 hrs.

In any of the preceding embodiments, the first surface of the disposableportion may include skin adhesive material for adhering the firstsurface to the skin of patient.

In any of the preceding embodiments, the reusable portion may include asealed housing, and the first and second surfaces of the disposableportion are breathable.

In one embodiment, a method of using the monitoring device described ina previous embodiment may include removing the reusable portion from thedisposable portion after a use of the monitoring device and replacingthe disposable portion.

The invention has now been described in detail for the purposes ofclarity and understanding. However, those skilled in the art willappreciate that certain changes and modifications may be practicedwithin the scope of the appended claims.

What is claimed is:
 1. A monitoring device for monitoring one or morephysiological parameters of a patient, the monitoring device comprising:a disposable portion comprising at least two electrodes for coupling toa portion of skin of the patient, a battery, a first set of electricalcontacts, a cover, a pocket for receiving a reusable portion, a ledgeportion, and a recess; wherein the pocket is defined by a plurality ofwalls provided below a top surface of the cover, wherein the recess isconfigured adjacent to one of the plurality of walls and to receive anuncoupling tool, wherein the recess intersects with the adjacent wall ata first and second corner, and wherein the adjacent wall that intersectswith the recess is structurally weaker than the walls associated withthe recess; and the reusable portion comprising a snap feature,processor, memory, a second set of electrical contacts, and sensingcircuitry coupled to the second set of electrical contacts, wherein thereusable portion is mechanically coupleable to the disposable portion,the plurality of walls surround the reusable portion, wherein the snapfeature engages with the ledge portion to retain the reusable portionwithin the pocket, and wherein the reusable portion is electricallycoupleable to the disposable portion through the first and secondelectrical contacts; wherein when the reusable portion and thedisposable portion are electrically coupled through the first and secondelectrical contacts, signals from the at least two electrodes are passedto the sensing circuitry and processed by the processor; wherein thesensing circuitry and the processor are powered from the battery throughthe coupled first and second electrical contacts; and wherein thereusable portion and the disposable portion are configured to bemechanically uncoupled by applying force with the uncoupling tool afterhaving been mechanically coupled, and the disposable portion isconfigured to be rendered unusable by the force causing the walladjacent to the recess to break and the ledge to be displaced to wherethe ledge is no longer in position to hold the reusable portion in thedisposable portion.
 2. The monitoring device of claim 1, wherein thebattery is a primary battery.
 3. The monitoring device of claim 2,wherein the reusable portion comprises a real time clock and a secondarybattery that powers the real time clock, and wherein when the reusableportion and the disposable portion are coupled through the first andsecond electrical contacts, the secondary battery is charged from theprimary battery through the first and second electrical contacts.
 4. Themonitoring device of claim 1, wherein: the reusable portion includes aunique reusable portion identifier stored in the reusable portion andaccessible to the processor; and the disposable portion includes aunique disposable portion identifier stored in the disposable portionand accessible to the processor.
 5. The monitoring device of claim 1,wherein the reusable portion further includes wireless communicationcircuitry through which information can be transmitted to an externaldevice, and a data interface comprising a connector for transmittingdata via wired connection using the connector.
 6. The monitoring deviceof claim 1, wherein the ledge is located adjacent to the recess.
 7. Themonitoring device of claim 6, wherein the ledge extends across a portionof the recess nearest to the pocket, and is affixed to the adjacent wallthat intersects with the recess.
 8. The monitoring device of claim 7,wherein the ledge extends into the pocket area to engage with the snapfeature associated with the reusable portion.
 9. The monitoring deviceof claim 6, wherein mechanically uncoupling the reusable portion fromthe disposable portion necessarily results in breaking the wall adjacentto the recess such that the snap feature is not engaged with the ledgeportion and renders the disposable portion unusable.
 10. The monitoringdevice of claim 1, wherein when the reusable portion is mechanicallycoupled within the disposable portion, the plurality of walls surroundthe reusable portion to form a water-resistant unit.
 11. The monitoringdevice of claim 1, wherein the reusable portion includes a humiditysensor configured to detect an ingress of water into the reusableportion.
 12. The monitoring device of claim 1, wherein the reusableportion can withstand multiple cleaning and disinfection cycles forreuse with a different patient without compromising the usability of thedevice.
 13. A monitoring device for monitoring one or more physiologicalparameters of a patient, the monitoring device comprising: a disposableportion comprising at least two electrodes for coupling to a portion ofskin of the patient, a battery, a first set of electrical contacts, acover, a pocket for receiving a reusable portion, a ledge portion, and arecess; wherein the pocket is defined by a plurality of walls providedbelow a top surface of the cover, wherein the recess is configuredadjacent to one of the plurality of walls and to receive an uncouplingtool, wherein the recess intersects with the adjacent wall at a firstand second corner; and wherein the adjacent wall that intersects withrecess is structurally weaker than the walls associated with the recess;and the reusable portion comprising a snap feature, processor, memory, asecond set of electrical contacts, and sensing circuitry coupled to thesecond set of electrical contacts, wherein the reusable portion ismechanically coupleable to the disposable portion, the plurality ofwalls surround the reusable portion, wherein the snap feature engageswith the ledge portion to retain the reusable portion within the pocket,and wherein the reusable portion is electrically coupleable to thedisposable portion through the first and second electrical contacts;wherein when the reusable portion and the disposable portion areelectrically coupled through the first and second electrical contacts,signals from the at least two electrodes are passed to the sensingcircuitry and processed by the processor; wherein the sensing circuitryand the processor are powered from the battery through the coupled firstand second electrical contacts; wherein the reusable portion and thedisposable portion are configured to be mechanically uncoupled byapplying force with the uncoupling tool after having been mechanicallycoupled, and the disposable portion is configured to be renderedunusable by the force causing the wall adjacent to the recess to breakand the ledge to be displaced to where the ledge is no longer inposition to hold the reusable portion in the disposable portion; andwherein the reusable portion comprises an outer surface, and wherein thedisposable portion comprises an outer surface, and wherein the outersurface of the reusable portion and the outer surface of the disposableportion are sized, shaped, and arranged such that mechanically couplingthe reusable portion to the disposable portion forms a contiguous outersurface of the monitoring device.